Calculators & Converters

    105 and 120 LCM

    LCM - Least Common Multiple Calculator

    LCM of 105 and 120 is equal to 840. The comprehensive work provides more insight of how to find what is the lcm of 105 and 120 by using prime factors and special division methods, and the example use case of mathematics and real world problems.

    what is the lcm of 105 and 120?
    lcm (105   120) = (?)
    105 => 3 x 5 x 7
    120 => 2 x 2 x 2 x 3 x 5

    = 3 x 5 x 7 x 2 x 2 x 2
    = 840
    lcm (105 and 120) = 840
    840 is the lcm of 105 and 120.

    where,
    105 is a positive integer,
    120 is a positive integer,
    840 is the lcm of 105 and 120,
    {3 x 5} in {3 x 5 x 7, 2 x 2 x 2 x 3 x 5} are the common factors of 105 and 120,
    {7 x 2 x 2 x 2} in {3 x 5 x 7, 2 x 2 x 2 x 3 x 5} are the uncommon factors of 105 and 120.

    Use in Mathematics: LCM of 105 and 120
    The below are some of the mathematical applications where lcm of 105 and 120 can be used:

    1. to find the least number which is exactly divisible by 105 and 120.
    2. to find the common denominator for two fractions having 105 and 120 as denominators in the unlike fractions addition or subtraction.
    Use in Real-world Problems: 105 and 120 lcm
    In the context of lcm real world problems, the lcm of 105 and 120 helps to find the exact time when two similar and recurring events with different time schedule happens together at the same time. For example, the real world problems involve lcm in situations to find at what time the bells A and B all toll together, if bell A tolls at 105 seconds and bell B tolls at 120 seconds repeatedly. The answer is that all bells A and B toll together at 840 seconds for the first time, at 1680 seconds for the second time, at 2520 seconds for the third time and so on.

    Important Notes: 105 and 120 lcm
    The below are the important notes to be remembered while solving the lcm of 105 and 120:
    1. The common prime factors and the remaining prime factors of 105 and 120 should be multiplied to find the least common multiple of 105 and 120, when solving lcm by using prime factors method.
    2. The results of lcm of 105 and 120, and the lcm of 120 and 105 are identical, it means the order of given numbers in the lcm calculation doesn't affect the results.
    For values other than 105 and 120, use this below tool:

    How-to: What is the LCM of 105 and 120?

    The below solved example with step by step work shows how to find what is the lcm of 105 and 120 by using prime factors method and division method.

    Solved example using prime factors method:
    What is the LCM of 105 and 120?

    step 1 Address the input parameters, values and observe what to be found:
    Input parameters and values:
    A = 105
    B = 120

    What to be found:
    find the lcm of 105 and 120

    step 2 Find the prime factors of 105 and 120:
    Prime factors of 105 = 3 x 5 x 7
    Prime factors of 120 = 2 x 2 x 2 x 3 x 5

    step 3 Identify the repeated and non-repeated prime factors of 105 and 120:
    {3, 5} are the most repeated factors and {7 x 2 x 2 x 2} are the non-repeated factors of 105 and 120.

    step 4 Find the product of repeated and non-repeated prime factors of 105 and 120:
    = 3 x 5 x 7 x 2 x 2 x 2
    = 840
    lcm(105 and 120) = 840

    Hence,
    lcm of 105 and 120 is 840


    Solved example using special division method:
    This special division method is the easiest way to understand the entire calculation of what is the lcm of 105 and 120.

    step 1 Address the input parameters, values and observe what to be found:
    Input parameters and values:
    Integers: 105 and 120

    What to be found:
    lcm (105, 120) = ?

    step 2 Arrange the given integers in the horizontal form with space or comma separated format:
    105 and 120

    step 3 Choose the divisor which divides each or most of the given integers (105 and 120), divide each integers separately and write down the quotient in the next line right under the respective integers. Bring down the integer to the next line if any integer in 105 and 120 is not divisible by the selected divisor; repeat the same process until all the integers are brought to 1 as like below:

    2105120
    210560
    210530
    310515
    5355
    771
    11

    step 4 Multiply the divisors to find the lcm of 105 and 120:
    = 2 x 2 x 2 x 3 x 5 x 7
    = 840
    LCM(105, 120) = 840

    The least common multiple for two numbers 105 and 120 is 840
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